1. Field of the Invention
The present invention relates to a retrieval method and a retrieval device by designation of recording time in an image recording/reproducing apparatus.
2. Description of the Prior Art
An image recording/reproducing apparatus for recording on a video tape an image picked up by a monitoring camera or its compressed data for each predetermined block, and reading and reproducing the data recorded on the video tape for each predetermined block has already been developed.
Such an image recording/reproducing apparatus is convenient if it can reproduce and output, by designating recording time, an image recorded at the designated recording time.
An object of the present invention is to provide, in an image recording/reproducing apparatus capable of reproducing and outputting, by designating recording time, an image recorded at the designated recording time, a retrieval method and a retrieval device by the designation of the recording time.
A retrieval method by designation of recording time in a first image recording/reproducing apparatus according to the present invention is a retrieval method by designation of recording time in an image recording/reproducing apparatus for recording, at the time of recording, input image data or its compressed data on a video tape by adding recording time information for each block including data corresponding to a plurality of fields and for each field included in the block as well as recording for each block VASS data representing the recording time information at the head of the block on a control track of the video tape, characterized by comprising the first step of specifying, when recording time is designated in order to perform retrieval by designation of the recording time, a block corresponding to the designated recording time on the basis of the VASS data, and storing in a second memory data in the block; the second step of retrieving, out of the plurality of fields included in the block stored in the second memory, the field having the recording time information corresponding to the designated recording time by binary search; and the third step of reproducing and outputting the data corresponding to the retrieved field.
A retrieval device by designation of recording time in a first image recording/reproducing apparatus according to the present invention is a retrieval device by designation of recording time in an image recording/reproducing apparatus for recording, at the time of recording, input image data or its compressed data on a video tape by adding recording time information for each block including data corresponding to a plurality of fields and for each field included in the block as well as recording for the block VASS data representing the recording time information at the head of the block on a control track of the video tape, characterized by comprising first means for specifying, when recording time is designated in order to perform retrieval by designation of the recording time, a block corresponding to the designated recording time on the basis of the VASS data, and storing in a second memory data in the block; second means for retrieving, out of the plurality of fields included in the block stored in the second memory, the field having recording time information corresponding to the designated recording time by binary search; and third means for reproducing and outputting the data corresponding to the retrieved field.
A retrieval method by designation of recording time in a second image recording/reproducing apparatus according to the present invention is a retrieval method by designation of recording time in an image recording/reproducing apparatus for storing, at the time of recording, input image data as basic image data in a first memory in a period of a predetermined number of fields, finding, with respect to each of the input image data corresponding to the fields between the field corresponding to the input image data which has been stored in the first memory and the field corresponding to the input image data which is to be subsequently stored in the first memory, the difference between the input image data and the basic image data which has been most newly stored in the first memory to produce difference data, recording on a video tape the basic image data and the difference data or their compressed data by adding, for each block including data corresponding to the plurality of fields and for each field included in the block, identification information indicating whether the field corresponds to the basic image data or the difference data and recording time information, and recording for each block VASS data representing the recording time information at the head of the block on a control track of the video tape, characterized by comprising the first step of specifying, when recording time is designated in order to perform retrieval by designation of the recording time, the block corresponding to the designated recording time on the basis of the VASS data, and storing in a second memory data in the block; the second step of retrieving, out of the plurality of fields included in the block stored in the second memory, the field having the recording time information corresponding to the designated recording time by binary search; the third step of reproducing and outputting, when the retrieved field corresponds to the basic image data, the field; and the fourth step of reproducing and outputting, when the retrieved field corresponds to the difference data, the field, corresponding to the basic image data, close to the field retrieved in the block specified at the first step.
An example of the fourth step is one comprising the steps of judging, when the retrieved field corresponds to the difference data, whether the field exists in the first half or the latter half of the block specified at the first step, reproducing and outputting, when it is judged that the retrieved field exists in the first half of the block specified at the first step, the field, corresponding to the basic image data, closest to the field retrieved out of the fields recorded after the retrieved field has been recorded, and reproducing and outputting, when it is judged that the retrieved field exists in the latter half of the block specified at the first step, the field, corresponding to the basic image data, closest to the retrieved field out of the fields recorded before the retrieved field has been recorded.
A retrieval device by designation of recording time in a second image recording/reproducing apparatus according to the present invention is a retrieval device by designation of recording time in an image recording/reproducing apparatus for storing, at the time of recording, input image data as basic image data in a first memory in a period of a predetermined number of fields, finding, with respect to each of the input image data corresponding to the fields between the field corresponding to the input image data which has been stored in the first memory and the field corresponding to the input image data which is to be subsequently stored in the first memory, the difference between the input image data and the basic image data which has been most newly stored in the first memory to produce difference data, recording on a video tape the basic image data and the difference data or their compressed data by adding, for each block including data corresponding to the plurality of fields and for each field included in the block, identification information indicating whether the field corresponds to the basic image data or the difference data and recording time information, and recording for each block VASS data representing the recording time information at the head of the block on a control track of the video tape, characterized by comprising first means for specifying, when recording time is designated in order to perform retrieval by designation of the recording time, the block corresponding to the designated recording time on the basis of the VASS data, and storing in a second memory data in the block; second means for retrieving, out of the plurality of fields included in the block stored in the second memory, the field having the recording time information corresponding to the designated recording time by binary search; third means for reproducing and outputting, when the retrieved field corresponds to the basic image data, the field; and fourth means for reproducing and outputting, when the retrieved field corresponds to the difference data, the field, corresponding to the basic image data, close to the field retrieved in the block specified by the first means.
An example of the fourth means is one comprising means for judging, when the retrieved field corresponds to the difference data, whether the field exists in the first half or the latter half of the block specified by the first means, means for reproducing and outputting, when it is judged that the retrieved field exists in the first half of the block specified by the first means, the field, corresponding to the basic image data, closest to the field retrieved out of the fields recorded after the retrieved field has been recorded, and means for reproducing and outputting, when it is judged that the retrieved field exists in the latter half of the block specified by the first means, the field, corresponding to the basic image data, closest to the retrieved field out of the fields recorded before the retrieved field has been recorded.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.